Rheumatic rash, or urticaria, is an allergic disease. Patients mainly manifest as flat bumps, wind clusters and itching on the skin, which can usually subside on their own within 24 hours. Patients with acute urticaria should first look for allergens, such as seafood, wine or drugs, and then stay away from allergens. 2. Urticaria can also develop in the internal organs, causing chest tightness, breathlessness, abdominal pain, anaphylaxis and other symptoms.